Security at high traffic installations such as airport terminals typically requires inspection of parcels passing certain checkpoints. Travelers generally prefer to avoid lengthy delays imposed by such inspections. Hence, in order to expedite inspection within the shortest period of time and with a minimum of privacy infringement, security systems have been established to screen the parcels, by radiating x-rays through the parcels to a detector to produce an image. This image can be viewed by a security agent on an image display device, and if found innocuous, will result in the package being passed on for delivery to the traveler or the transport. If the image suggests further inspection is required, the package may be isolated from others and physically searched in more detail to ascertain and assess its contents.
Carry-on parcels to be screened at an airport are usually inspected via an x-ray screening system. Passengers' place parcels onto an input conveyor belt. The belt transports the parcels through the inspection system, which x-rays the parcels and presents images to the x-ray system operator displaying the contents of the parcels on a video monitor. When the x-ray system operator observes a potentially prohibited item appear on the monitor, he may provide a signal to a search operator. This signal may constitute an oral statement, or be exhibited as an audio or visual alarm indicator implemented electronically via a push-button that provides a delayed indication when the parcel in question reaches the exit of the x-ray system. The identity of the parcel to be further examined is sometimes not clearly indicated. On occasion, the search operator examines a parcel that does not conform to the parcel the x-ray system operator intended when the alarm was initiated. Additionally, the search operator has no indication of what is in the parcel to be searched, or what aroused the x-ray operator's suspicion. On occasion, this may permit a parcel that should be physically searched for a particular potential item of contraband to escape the physical inspection process.
One solution proposed in the past includes transmitting an integrated image from multiple x-ray emitters to record on a video disk and transfer to a monitor for continuous display, from which it can be sent by a monitor operator to a parcel sorter who diverts the parcel to a separate inspection desk for further examination. A more effective method to properly identifying parcels to be segregated from others for more detailed inspection is needed in the security industry.